79 



and separated from each other by a lone conmiisnuro (c.c), 

 which is composed only of nerve fibres. From near the out- 

 er end of cither, a single large pallial nerve passes, to 

 be distributed to the anterior part of the mantle v;hich 

 underlies the shell, and forms the cephalic hood. From 

 near the inner ends of the ganglia large connectives pass 

 around the sides of the mouth to the pedal ganglia (p); 

 and, from the posterior outer ends, the cerebro-viscoral 

 connectives pass posteriorly to the visceral ganglia. The 

 pedal ganglia give off several pairs of large nerves which 

 innervate the foot. 



The Visceral Ganglia. - The two visceral (v. fig. 10,60) 

 ganglia of the larva fuse into the single mass which lies 

 very far posteriorly in the adult (v. fig. 10). After leav- 

 ing the cerebro-pleural ganglia, their connectives with 

 the visceral pass along the sides of the "liead" under the 

 anterior gill filaments; but , posterior to the large adduc- 

 tor muscle, they take up a more median position, among the 

 tissues of tne liver and genital organs. In front of the 

 visceral ganglia they come to lie close together, internal 



